Field of the Invention
The present invention relates to an organic light-emitting diode (OLED) display panel and an OLED display device.
Discussion of Related Art
Organic light-emitting diode (OLED) display devices (also referred to as organic light-emitting display devices) have recently been prominent as next generation display devices. Such OLED display devices have inherent advantages, such as relatively fast response speeds, high contrast ratios, high light emitting efficiency, high luminance levels, and wide viewing angles, since OLEDs able to emit light by themselves are used therein.
Each sub-pixel disposed on an OLED display panel (also referred to as an organic light-emitting display panel) basically includes a driving transistor driving an OLED, a switching transistor transmitting a data voltage to a gate node of the driving transistor, and a capacitor maintaining a certain level of voltage for a period of a single frame.
The driving transistor in each sub-pixel has characteristics that may differ according to driving transistors, such as a threshold voltage and mobility thereof.
The driving transistors may deteriorate along with the lapse of driving period, whereby the characteristics thereof change. Since the driving transistors may experience different degrees of deterioration during the same driving time, the characteristics of one driving transistor may have a difference from those of another driving transistor.
Such differences in the characteristics between the driving transistors may produce differences in degrees of luminance, leading to non-uniform luminance in the OLED display panel.
Therefore, technologies for compensating for the differences in characteristics by sensing the characteristics of individual driving transistors have been developed. However, regardless of the compensation for the differences in the characteristics of the individual driving transistors, the sensed values thereof change for certain reasons, thereby lowering the accuracy of sensing. Thus, there has not been proper compensation for the differences in characteristics (i.e. compensation for the luminance differences) to date. This problem consequently leads to poor image quality.